ML20211E351
| ML20211E351 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/15/1986 |
| From: | Miraglia F Office of Nuclear Reactor Regulation |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| TAC-61456, NUDOCS 8610220424 | |
| Download: ML20211E351 (3) | |
See also: IR 05000312/1986008
Text
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October 15, 1986
,
MEMORANDUM FOR: Dennis F. Kirsch, Director
Division of Reactor Safety and Projects
Region V
FROM:
Frank J. Miraglia, Director
Division of PWR Licensing-B
Office of Nuclear Peactor Regulation
SUBJECT:
TRANSFER OF LEAD RESPONSIBILITY FOR REVIEW 0F TECHNICAL ISSUES
ASSOCIATED WITH DEGRADED BATTERIES (TIA 86-4 FM)
REFERENCE:
Memorandum from D.F. Kirsch to F.J. Miraglia,
Transfer of Lead Responsibility on Degraded
Batteries at Rancho Seco, dated May 2, 1986.
In the referenced memo, you requested that we assume responsibility for the
review of certain technical issues identified in NRC Inspection Report
50-312/86-08 that involve several unresolved items concerning the licensee's
124 volt DC station batteries. This request was clarified during a telephone
conversation between NRR and Region V on June 5, 1986 with an agreement that
NRR should address the following concerns:
(1) Define the safety significance of the NRC inspectors findings as they
relate to battery seismic qualification and operability.
(2)
Provide NRR's technical justification for the necessity of performing the
IEEE 450 " performance" and " service" testing.
We have completed our evaluation _and have concluded, due to the reported
deterioration of the cell plates and improper cell spacing, seismic vibrations
could have led to battery failure and loss of the 125 volt DC system.
Concerning surveillance program adequacy, we conclude that the IEEE 450
specified " performance" and " servi.ce" tests are necessary in order to
demonstrate compliance with the requirements of General Design Criterion 17
of Appendix A to 10 CFR 50. Our Safety Evaluation is attached for your
information.
This completes TIA 86-4 FM.
Sincerely,
Original alanua .ay
8610220424 861015
Prook J. Miraglia
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Frank J. Miraglia, Director
Division of PWR Licensing-B
Office of Nuclear Reactor Regulation
Enclosure: As stated
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MEMORANDUM FOR: Dennis F. Kirsch, Director
Division of Reactor Safety and Projects
Region V
FROM:
John F. Stolz, Director
PWR Project Directorate #6
Division of PWR Licensing-B
SUBJECT:
TRANSFER OF LEAD RESPONSIBILITY FOR REVIEW 0F TECHNICAL ISSUES
ASSOCIATED WITH DEGRADED BATTERIES (TIA 86-4 FM)
REFERENCE:
Memorandum from D.F. Kirsch to F.J. Miraglia,
Transfer of Lead Responsibility on Degraded
Batteries at Rancho Seco, dated May 2, 1986.
In the referenced memo, you requested that we assume responsibility for the
review of certain technical issues identified in NRC Inspection Report
50-312/86-08 that involve several unresolved items concerning the licensee's
124 volt DC station batteries. This request was clarified during a telephone
conversation between NRR and Region V on June 5, 1986 with an agreement that
NRR should address the following concerns:
(1) Define the safety significance of the MRC inspectors findings as they
relate to battery seismic qualification and operability.
~(2) Provide NPR's technical justification for the necessity of performing the
IEEE 450 " performance" and " service" testing.
We have completed our evaluation and have concluded, due to the reported
deterioration of the cell plates and improper cell spacing, seismic vibrations
could have led to battery failure and loss of the 125 volt DC system.
Concerning surveillance program adecuacy, we conclude that the IEEE 450
specified " performance" and " service" tests are necessary in order to
demonstrate compliance with the requirements of General Design Criterion 17
of Appendix A to 10 CFR 50. Our Safety Evaluation is attached for your
information.
This completes TIA 86-4 FM.
Sincerely,
John F. Stolz, Director
PWR Project Directorate #6
Division of PWR Licensing-B
Enclosure: As stated
DISTRIBUTION
SMiner
Docket File
GKalman
NRC PDR
RWeller
Local PDR
RIngram
Memo File
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Enclosure
Rancho Seco Nuclear Generating Station
Safety Evaluation
Seismic Qualification / Operability
Concern:
Define the safety significance of the NRC inspectors findings as they
relate to battery seismic qualification and operability.
Evaluation
The concerns raised by the NRC Inspection Report 50-312/86-08 are the
potentially unsatisfactory seismic capability due to an as-found
condition different from that of the design, and battery seismic
capability degradation due to deterioration of the cell plates in the
area of their connection to the cell posts. Based on seismic testing,
the vendor (GNB) of the Rancho Seco batteries specified that the gap
spacing between the end cell and the end stringer of the battery rack
,
should not be greater than 1/4 inch and the gap spacing between the cell
and the side stringer of the battery rack should be less than 3/8 inch.
The NRC inspector's report indicates that gap spacings greater t.han those
specified were found at Rancho Seco.
_
The significance of this deviation is that in the event of an earthquake
there could be excessive inter-cell and cell to rack movement. This
excessive differential movement could result in impacts causing damage to
the cell containers. Further, with gaps present, the major restraint on
cell movement may be the inter-cell connectors and the cell terminal
posts. The reported deterioration of the cell plates in the area of the
cell posts and the additional stress on the posts through the connectors
due to seismic vibrations could lead to battery failure and the loss of
the 125 volt DC system.
Surveillance Program
Concern:
Provide NRP's technical justification for the necessity of performing the
IEEE 450 " performance" and " service" testing.
Evaluation
The " Performance" test demonstrates the purchased capacity of the battery
whereas the " service test" demonstrates the ability of the battery tn
meet its design safety function, commonly known as duty cycle (the two
hour test in which the largest one minute load and steady loads are
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supposed to be adequately supplied by the hattery). The performance test
assures " capacity" whereas the service test assures " capability" as
required by GDC 17 to be the safety function of onsite, Class IE DC
systems. The licensee has committed in Section 8.1 of their FSAR to
comply with NRC General Design Criteria.
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